Data and Complexity Hiding

/*This code was written by A. El-Gadi of Tripoli University for educational purposes. It illustrates the concept of data hiding and complexity hiding. For any questions  and discussion use the comment section below.*/

 

#include <iostream>

using namespace std;

class Box{/* A box is assumed to be a rectangular cuboid. The box is also assumed to be of uniform thickness which includes the cover. Please keep in mind that this example is hypothetical and bears no affinity to the reality of determining box characteristics whatsoever.*/
private:
    double st;//Stiffness
    double den;//Density: 7.82 steel/0.55 wood/0.7 cardboard
    int matid;//Material id: (1) cardboard (2) wood (3) steel
    double wd,dp,ht,tk;//width, depth, height, thickness
    double outervolume(){return wd*dp*ht;}
    bool impossiblebox(double w,double d,double h,double t){
                bool truthvalue;
                truthvalue=w>=0&&d>=0&&h>=0;
                truthvalue=truthvalue&&w>2*t&&d>2*t&&h>2*t;
                return !truthvalue;
                }
               
   

public:
    Box():st(0), den(0), matid(0), wd(0), dp(0),ht(0){}
    Box(int m,double w,double d,double h,double t){
        if(!impossiblebox(w,d,h,t)){
                matid=m; wd=w; dp=d; ht=h; tk=t;
                switch(m)
                {
                    case 1: st=0.5;den=1; break;
                    case 2: st=1.5;den=0.7; break;
                    case 3: st=2.9;den=0.1;
                }
                }
    }

    double capacity(){return (wd-2*tk)*(dp-2*tk)*(ht-2*tk);}

    double tare(){return (outervolume()-capacity())*den;}//The weight of an empty box is called: tare
   
    double maxLoad(){return st*tk*den*1.4;}
};


int main(){

Box b1(2,100,50,40,3);
Box b2(2,100,50,40,70);
cout << b1.maxLoad()<<' ';
cout << b2.maxLoad();

return 0;
}